drm/nouveau/mxm: initial implementation of dcb sanitisation

The DCB table provided by the VBIOS on most MXM chips has a number of
entries which either need to be disabled, or modified according to the
MXM-SIS Output Device Descriptors.

The x86 vbios code usually takes care of this for us, however, with the
large number of laptops now with switchable graphics or optimus, a lot
of the time nouveau is responsible for POSTing the card instead - leaving
some fun situations like, plugging in a monitor and having nouveau decide
3 connectors actually just got plugged in..

No MXM-SIS fetching methods implemented yet.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/Makefile

@@ -11,7 +11,7 @@ nouveau-y := nouveau_drv.o nouveau_state.o nouveau_channel.o nouveau_mem.o \
              nouveau_display.o nouveau_connector.o nouveau_fbcon.o \
              nouveau_hdmi.o nouveau_dp.o nouveau_ramht.o \
 	     nouveau_pm.o nouveau_volt.o nouveau_perf.o nouveau_temp.o \
-	     nouveau_mm.o nouveau_vm.o \
+	     nouveau_mm.o nouveau_vm.o nouveau_mxm.o \
              nv04_timer.o \
              nv04_mc.o nv40_mc.o nv50_mc.o \
              nv04_fb.o nv10_fb.o nv30_fb.o nv40_fb.o nv50_fb.o nvc0_fb.o \

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -5382,6 +5382,9 @@ bit_table(struct drm_device *dev, u8 id, struct bit_entry *bit)
 	struct nvbios *bios = &dev_priv->vbios;
 	u8 entries, *entry;
 
+	if (bios->type != NVBIOS_BIT)
+		return -ENODEV;
+
 	entries = bios->data[bios->offset + 10];
 	entry   = &bios->data[bios->offset + 12];
 	while (entries--) {
@@ -5832,7 +5835,7 @@ dcb_table(struct drm_device *dev)
 	return NULL;
 }
 
-u8 *
+void *
 dcb_outp(struct drm_device *dev, u8 idx)
 {
 	u8 *dcb = dcb_table(dev);
@@ -6663,6 +6666,10 @@ nouveau_bios_init(struct drm_device *dev)
 	if (ret)
 		return ret;
 
+	ret = nouveau_mxm_init(dev);
+	if (ret)
+		return ret;
+
 	ret = parse_dcb_table(dev, bios);
 	if (ret)
 		return ret;
@@ -6703,5 +6710,6 @@ nouveau_bios_init(struct drm_device *dev)
 void
 nouveau_bios_takedown(struct drm_device *dev)
 {
+	nouveau_mxm_fini(dev);
 	nouveau_i2c_fini(dev);
 }

drivers/gpu/drm/nouveau/nouveau_bios.h

@@ -315,7 +315,7 @@ struct nvbios {
 };
 
 void *dcb_table(struct drm_device *);
-u8 *dcb_outp(struct drm_device *, u8 idx);
+void *dcb_outp(struct drm_device *, u8 idx);
 int dcb_outp_foreach(struct drm_device *, void *data,
 		     int (*)(struct drm_device *, void *, int idx, u8 *outp));
 u8 *dcb_conntab(struct drm_device *);

drivers/gpu/drm/nouveau/nouveau_drv.c

@@ -124,6 +124,10 @@ MODULE_PARM_DESC(ctxfw, "Use external HUB/GPC ucode (fermi)\n");
 int nouveau_ctxfw;
 module_param_named(ctxfw, nouveau_ctxfw, int, 0400);
 
+MODULE_PARM_DESC(ctxfw, "Santise DCB table according to MXM-SIS\n");
+int nouveau_mxmdcb = 1;
+module_param_named(mxmdcb, nouveau_mxmdcb, int, 0400);
+
 int nouveau_fbpercrtc;
 #if 0
 module_param_named(fbpercrtc, nouveau_fbpercrtc, int, 0400);

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -793,6 +793,7 @@ struct drm_nouveau_private {
 	struct nouveau_vm *chan_vm;
 
 	struct nvbios vbios;
+	u8 *mxms;
 	struct list_head i2c_ports;
 
 	struct nv04_mode_state mode_reg;
@@ -864,6 +865,7 @@ extern char *nouveau_perflvl;
 extern int nouveau_perflvl_wr;
 extern int nouveau_msi;
 extern int nouveau_ctxfw;
+extern int nouveau_mxmdcb;
 
 extern int nouveau_pci_suspend(struct pci_dev *pdev, pm_message_t pm_state);
 extern int nouveau_pci_resume(struct pci_dev *pdev);
@@ -1108,6 +1110,10 @@ extern int call_lvds_script(struct drm_device *, struct dcb_entry *, int head,
 			    enum LVDS_script, int pxclk);
 bool bios_encoder_match(struct dcb_entry *, u32 hash);
 
+/* nouveau_mxm.c */
+int  nouveau_mxm_init(struct drm_device *dev);
+void nouveau_mxm_fini(struct drm_device *dev);
+
 /* nouveau_ttm.c */
 int nouveau_ttm_global_init(struct drm_nouveau_private *);
 void nouveau_ttm_global_release(struct drm_nouveau_private *);